In recent years, a problem such as delays, loss, noise or the like has been emphasized in signal transmission between LSI chips. In personal computers and mobile communication devices such as mobile phones in particular, noise interference between various radio signals and electric signals in the devices has become controversial. More specifically, EMI (Electromagnetic Interference) that affects other electronic devices or circuits through emission of electromagnetic noise and EMS (Electromagnetic Susceptibility) that receives influences of electromagnetic noise from other electronic devices or circuits have become controversial. Therefore, a concept called as EMC (Electromagnetic Compatibility) taking both EMI and EMS into consideration has become more and more important in the field of device design.
Under such circumferences, there is an increasing trend to apply optical signals which are not only high speed and low loss but also free of electromagnetic noise to signal transmission between LSI chips. However, since a finite power supply such as a battery is used in a mobile device, electronic parts in the device are strongly required to achieve low power consumption. The same applies even when light is used as a signal transmitter. As a low power optical wiring system, JP-A No. 3-58532 (Kokai) (hereinafter, “Patent Document 1”) and JP-A No. 2004-153442 (Kokai) (hereinafter, “Patent Document 2”) disclose optical wiring systems that reduce power consumption by shortening a time to supply a light-emitting element with a driving current. Furthermore, JP-A No. 2006-216849 (Kokai) (hereinafter, “Patent Document 3”) and JP-A No. 4-283978 (hereinafter, “Patent Document 4”) disclose optical wiring systems that reduce power consumption by shortening a time to supply the light-emitting element with a bias current.